Per the IRS Other Deduction Questions webpage:
My spouse and I are filing separate returns. How can we split our itemized deductions?
If you and your spouse file separate returns and one of you itemizes deductions, the other spouse must also itemize, because in this case, the standard deduction amount is zero for the non-itemizing spouse.
- You may be able to claim itemized deductions on a separate return for certain expenses that you paid separately or jointly with your spouse.
- When paid from separate funds, expenses are deductible only by the spouse who pays them.
- For example, if otherwise deductible medical expenses are paid from an account owned by one of the spouses or in a community property state from an account that's the separate property of one of the spouses under the laws of that state, only that spouse may claim a deduction for the expenditure.
- When expenses are paid from funds owned by both spouses, such as from a joint checking account or accounts considered community property under the laws of the state in which the spouses reside, you should generally split the deduction between you and your spouse.
- For example, if amounts are paid from a joint checking account for interest on a residence both you and your spouse own, you would each deduct half of the mortgage interest paid on your separate returns.
- However, if only one of you is eligible for a deduction for an expense (for example, real estate taxes on a property owned only by the eligible spouse), only the spouse who is eligible for the deduction is allowed to claim it, even if the expense is paid from joint funds. Each spouse must maintain records documenting who is considered to have paid the expense.
Note. Filing a tax return with the status Married Filing Separate may limit or disqualify your eligibility to claim certain deductions or credits.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.